Part A
ADC121S101CIMF
Texas Instruments
- Lifecycle
- Active
- Stock
- 3205 PCS
- Package
- SOT-23-6
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Compatible functional replacement candidate
The ADC121C021CIMK is a functional replacement candidate for the ADC121S101CIMF, sharing the same 12-bit resolution, SPI interface, and SOT-23-6 footprint, though the I2C-based control interface and differing supply voltage range require validation before substitution in a given design.
Resolution
High match
Digital Interface
Validation required
Package Type
High match
Supply Voltage Range
Validation required
Parts at a glance
Part B
ADC121C021CIMK
Texas Instruments
- Lifecycle
- Active
- Stock
- 5279 PCS
- Package
- TSOT-23-6
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | ADC121S101CIMF | ADC121C021CIMK | Why it matters |
|---|---|---|---|
| Resolution | 12 bit | 12 bit | Both provide 12-bit resolution, so measurement granularity is equivalent. |
| Number of Input Channels | 1 single-ended | 1 single-ended | Both are single-channel devices; channel count is not a differentiator. |
| Sampling Rate | Up to 1 MSPS | Up to 188.9 kSPS | The S101 supports much faster conversion, which matters for high-speed signal acquisition. |
| Supply Voltage Range | 2.7 V to 5.25 V | 2.7 V to 5.5 V | Slightly wider upper supply range on the C021 allows use in 5 V systems with more margin. |
| Interface Type | SPI (serial) | I2C (2-wire) | Different digital interfaces mean the parts are not drop-in compatible without bus redesign. |
| Package | SOT-23-6 | SOT-23-6 | Same package footprint simplifies PCB layout substitution. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +125 °C | Identical temperature ratings suit the same industrial environments. |
| Power Consumption (typical) | ~2.5 mW at 3.3 V, 1 MSPS | ~0.5 mW at 3.3 V, 188.9 kSPS | Lower power per conversion on the C021 benefits battery-powered designs. |
| Internal Reference | No (external reference required) | No (external reference required) | Both require an external reference, so reference circuitry must be provided in either case. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADC121S101CIMF | ADC121C021CIMK |
|---|---|---|
| Supplier | - | Texas Instruments |
| Part Status | Obsolete | Obsolete |
| Number of Bits | 12 | 12 |
| Sampling Rate(Per Second) | 1M | 188.9k |
| Number of Inputs | 1 | 1 |
| Input Type | Single Ended | Single Ended |
| Data Interface | SPI, DSP | I²C |
| Configuration | S/H-ADC | S/H-ADC |
| Ratio - S / H: ADC | 1:1 | 1:1 |
| Number of A/D Converters | 1 | 1 |
| Architecture | SAR | SAR |
| Reference Type | Supply | Supply |
| Voltage - Supply, Analog | 2.7V ~ 5.25V | 2.7V ~ 5.5V |
| Voltage - Supply, Digital | 2.7V ~ 5.25V | 2.7V ~ 5.5V |
| Operating Temperature | -40°C ~ 125°C | -40°C ~ 105°C |
Frequently asked questions
What are the key differences between the ADC121S101CIMF and the ADC121C021CIMK?
The ADC121S101CIMF is a 12-bit, 1 MSPS successive-approximation ADC with a single-ended input and an SPI-compatible serial interface, supplied in a SOT-23-6 package. The ADC121C021CIMK is a 12-bit, 188.9 kSPS I2C-compatible ADC with an alert function and a programmable address, supplied in a SOT-23-6 package. The primary differences are the serial interface (SPI vs I2C), the maximum sample rate (1 MSPS vs 188.9 kSPS), and the presence of an I2C alert output on the ADC121C021CIMK.
Are the ADC121S101CIMF and ADC121C021CIMK pin-compatible?
No. Although both devices are offered in a 6-pin SOT-23 package, their pin functions differ because one uses an SPI interface and the other uses an I2C interface. The ADC121S101CIMF provides CS, SCLK, SDATA, and a single analog input, while the ADC121C021CIMK provides SDA, SCL, an alert output, and a single analog input. A direct drop-in replacement is therefore not possible without PCB and firmware changes.
Can the ADC121S101CIMF and ADC121C021CIMK be used as direct substitutes for each other?
No. They are not direct substitutes. The ADC121S101CIMF uses an SPI-compatible interface at up to 1 MSPS, whereas the ADC121C021CIMK uses an I2C-compatible interface at up to 188.9 kSPS with an alert function. Substitution requires redesign of the digital interface, review of the timing and throughput requirements, and validation against the target system.
What are the maximum sample rates of the ADC121S101CIMF and ADC121C021CIMK?
The ADC121S101CIMF supports a maximum conversion rate of 1 MSPS. The ADC121C021CIMK supports a maximum conversion rate of 188.9 kSPS. The higher throughput of the ADC121S101CIMF makes it suitable for faster signal acquisition, while the ADC121C021CIMK is intended for lower-speed I2C-based monitoring applications.
What serial interfaces do the ADC121S101CIMF and ADC121C021CIMK use?
The ADC121S101CIMF uses an SPI-compatible serial interface with chip select, serial clock, and serial data lines. The ADC121C021CIMK uses an I2C-compatible two-wire interface with serial data and serial clock lines, and it supports a programmable I2C address plus an alert output. The interface choice is a primary factor when selecting between the two devices.
What are the resolution and supply voltage specifications for these two ADCs?
Both the ADC121S101CIMF and the ADC121C021CIMK are 12-bit analog-to-digital converters. Both operate from a single supply in the 2.7 V to 5.5 V range, which allows them to be used in mixed 3.3 V and 5 V systems. Designers should confirm the exact supply and reference conditions against the respective manufacturer datasheets for the target application.
Which device is better suited for I2C-based system monitoring?
The ADC121C021CIMK is better suited for I2C-based system monitoring because it includes an I2C-compatible interface, a programmable address, and an alert output that can notify the host when a conversion result crosses a programmed threshold. The ADC121S101CIMF lacks these I2C features and is intended for SPI-based, higher-speed acquisition.
Do both devices support the same package and operating temperature range?
Both the ADC121S101CIMF and the ADC121C021CIMK are offered in a 6-pin SOT-23 package and are specified for the industrial temperature range of -40°C to +85°C. However, because their pin functions and interfaces differ, the shared package and temperature range do not make them interchangeable without design changes.